| SORTING SIGNALS of PROTEIN TRAFFIC for the Nucleus, Endomembranes, or Secretion | |||
|
SIGNAL |
Description |
Destination |
Protein contains |
|
Nuclear Localizing Signal |
located
anywhere in polypeptide; 4 to 8 aa's, nucleoplasmin = [n-Pro-Lys-Lys-Lys-Arg-Lys-Val-c] |
cytoplasm to nucleus |
Nucleoplasmin:
contains a Nuclear Localizing Signal |
|
ER Signal |
sequence of 6
to 12 aa's near N-terminal of mostly non-polar aa's |
into E.R. |
ER Signal &
ER Retention Signal |
|
ER Retention Signal |
sequence of 4
aa's, at c-terminal LYS-ASP-GLU-LEU- |
within E.R. |
ER Signal & ER Retention Signal |
|
Golgi Retention Signal |
sequence of
20 hydrophobic non-polar aa's - forms transmembrane domain flanked by basic aa's |
into Golgi |
ER Signal & Golgi Retention Signal |
|
Lysosome Targeting |
within
polypeptide - basic charged aa's - leads to covalent links of mannose-6-P |
into Lysosome |
ER Signal & Lysosomal Targeting Signal |
| Plasma Membrane |
ER signal with stretch of non-polar hydrophobic transmembrane domain's that anchor it in membrane |
Plasma Membrane | ER
Signal & hydrophobic domain aa's |
| Secretion | ER proteins encapsulated into vesicles | Secretion | ER Signal only © |